HYTOS

import numpy as np

import cv2, os

rootPath = 'E:\Projects\LPG\drawings_'

imgList = os.listdir(rootPath)

startX, startY, endX, endY = 6783, 121, 8223, 5820

print('start')

for imgPath in imgList:

    fullPath = os.path.join(rootPath, imgPath)

    img = cv2.imread(fullPath, cv2.IMREAD_GRAYSCALE)

    img = cv2.rectangle(img, (startX, startY), (endX, endY), 255, -1)

    originPath = os.path.splitext(fullPath)

    newPath = originPath[0] + '_new' + originPath[1]

    cv2.imwrite(newPath, img)

print('finished')